Production of titanic oxide



Patented May 13, 1930 UNITED STATES PATENT OFFICE MORITZ SGHNETKA, OFLEVERKUSEN-ON-THE-RHINE, GERMANY, ASSIGNOB TITANIUM PIGMENT (30., INC.,01 NEW.YOBK, N. Y.

PRODUCTION OF TITANIC OXIDE No Drawing. Application filed June 25, 1928,Serial No. 288,296, and in Germany September 6, 1987.

The present invention concerns the hydrolytic precipitation of whitetitanic acid in the presence of a compound of the groupcomprising'hydrofluoric acid and water sol- 5 uble fluorides.

The principal difficulty in the manufacture of titanic acid or of whitetitanium pigments consists in obtaining on hydrolysis a pure whiteprecipitate which persists even on ignition.

In accordance with the present invention white precipitation products,stable to ignition, are obtained by carrying out the hydrolysis fromsulfuric acid solution in the presence of hydrofluoric acidor of solublefluorides. In addition to the favourable influence exerted in regard tothe stability of the white color ofthe precipitated titanic acid, thesaid hydrolytic precipitation is also considerably facilitated, with theresult that v the duration or temperature of the hydrolysis is reduced.Moreover, the titanic acid, precipitated by boiling at the ordinarypressure in the presence of hydrofluoric acid or fluorides can befiltered more easily than that obtained under similar conditions from asolution free from fluorides. The former appears in a more granularstate, the latter in a slimy form.

The. invention is illustrated by the following example; without limitingit thereto:

EwmnpZe.-600 kgs. of worked up ilmenite, containing 8.6% T10 3.7% FeOand 22% total sulfuric acid, are dissolved in water, 13 kgs. of 45%hydrofluoric acid are added and heating is effected to boiling (underordinary pressure). In order to prevent the concentration of freesulfuric acid, the mantity of which is increasing by hydro ysis, frombecoming too high, 200 kgs.. of water are added gradually duringthehydrolysis. After boiling for 6 hours, 45.8 k s.=89% of thetitanicacid are separated. t is easily filtered and even after ignition at 900C. remains pure white.

Icla1m: 1. In the process for thehydrolytic precipitation of whitetitanic acid from sulfuric acid solutions containing titanium sulfate 50and iron sulfate, the step which comprises carrying out theprecipitation in the presence of a compound of the. group consistin ofhydrofluoric acid and water-soluble fluorldes.

2 In the process for the hydrolytic rec1p1tat1on of white titanic acidfrom sul uric acid solutions containing titanium sulfate and ironsulfate, the step which comprises carryln out the precipitation in thepresence of hydrofluor c acid.

In testimony whereof I have hereunto set my hand. MORITZ SCHNETKA.[L.S.]

